Samsung Ue40H5500AY , T-con problems .

[amennone]

T-Con RUNTK5538tp

Hi, the TV has problems with the screen, the image is dark and undefined.
There is no VGH power supply.
With an external 32 volts power supply everything is ok.
How is VGH managed?
what can i check?
Thanks and good job

[neilc6]

Re: Samsung Ue40H5500AY , T-con problems .

Power up the TV with only one side connected at a time between the tcon and panel. If one side shows a clean image, you have a panel fault on the bad side.

[angelos]

Re: Samsung Ue40H5500AY , T-con problems .

So Neilc6, are you saying that the VGH boost buck converter is shutting down due to an overcurrent condition? If so, then why does the external power supply feeding this VGH work. If there was a short then smoke and flames should come out of the TCOF IC. It could just be the DC to DC buck converter IC that failed meaning you neither need to change the chip or the TCON. Am i right?
I do agree that if there are two ribbons feeding the panel then you can isolate the problem by removing them one by one..

Regards

[dick_barton]

Re: Samsung Ue40H5500AY , T-con problems .

It may not be a dead short circuit but somethng taking more current than the VGH circuit can supply.

It may be a fault with the VGH circuit itself, no longer able to supply the required current.

As Neilc6 says it may well be a panel problem drawing more current than it should, but not enough to go up in smoke.

The smd capacitors on the panel circuit board are known to fail.

[angelos]

Re: Samsung Ue40H5500AY , T-con problems .

Thanks for clearing that up Dick. So a capacitor shorting to say 40 ohms would overload the circuit but not cause it to burn?

[dick_barton]

Re: Samsung Ue40H5500AY , T-con problems .

Yes, that's correct.
The resistance or fault could exceed the available current VGH could supply but show no sign.

[amennone]

Re: Samsung Ue40H5500AY , T-con problems .

with external power supply with voltage 30v I have a current of 110 milliamps.

[amennone]

Re: Samsung Ue40H5500AY , T-con problems .

images

[amennone]

Re: Samsung Ue40H5500AY , T-con problems .

immagini

[dick_barton]

Re: Samsung Ue40H5500AY , T-con problems .

If I am correct the picture looks very much like a side tab problem. It would be worthwhile searching the forum posts which show and discuss this issue.